Why OncoMed Pharmaceuticals, Unilife, and Tesla Motors Are Today's 3 Best Stocks

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Despite another month of incredible strong U.S. auto sales figures, the broad-based S&P 500 couldn't mount a comeback and ended the day lower for a third straight session.

There were two primary factors weighing down the S&P 500 today. First, the endless uptrend in the S&P 500 has investors concerned that the Federal Reserve may taper its monthly bond-buying stimulus known as QE3 earlier than expected, which means less "free money" being added to the market and the potential for higher interest rates. Once again, it's a bit of a Catch-22, where a good market environment means the end of the Fed's ongoing stimulus, while bad economic news gets cheers from the crowd because QE3 will continue.

The other factor pushing the iconic index lower was weakness in the consumer-goods sector. Initial estimates from Black Friday show a huge boost for direct-to-consumer-based sales while bricks-and-mortar companies saw lower-priced and deeply discounted items flying off their shelves. Overall, this reinforces the trend we saw during the back-to-school season that it's going to be a tough holiday season for retailers.

U.S. auto sales, though, were the one bright spot. General Motors, Ford, and Chrysler reported year-over-year November unit sale increases of 13.9%, 7.1% and 16%, respectively, while Honda Motor actually reported a slight dip in sales. As has been the case, GM's redesigned Silverado and Sierra continue to fuel sales while Ford is cruising in the fuel-efficient compact car category. Furthermore, the industry is on pace to sell more than 16 million seasonally adjusted units, which is its highest level since before the recession.

By day's end, the S&P 500 finished lower by 5.75 points (-0.32%) to close at 1,795.15, which is still less than 1% from a new all-time high.

Topping the charts to the upside was OncoMed Pharmaceuticals , which spiked higher by as much as 126% at one point after striking a collaborative agreement with Celgene to develop up to six cancer stem cell therapies. The deal involves Celgene paying OncoMed $155 million upfront, making a $22.5 million investment in OncoMed's common stock, and could net OncoMed billions in milestone payments. Based on its press release, OncoMed could earn up to $790 million in milestones for its lead drug, demcizumab, an additional $505 million for an anti-DLL4/VEGF bispecific antibody, and up to $440 million for four additional anti-CSC therapies, each. If OncoMed shareholders had any fears of running out of cash anytime soon, those are now gone. Shares ended the day higher by 97.9%.

Continuing the theme of striking deals, Unilife , which makes injectable drug delivery systems, rose 16.6% after striking a deal with Novartis to supply clinical products from one of its injectable drug delivery systems for one of Novartis' early stage clinical compounds. The deal nets Unilife milestone payments totaling $15 million, and it can earn additional royalties on sales of the syringes. In addition, Novartis may extend the deal to 2024. This marks the second commercial deal for Unilife in just the past month and has put the company on the path toward shrinking its cash burn and possibly being profitable as early as next year.

Finally, electric-vehicle maker Tesla Motors rallied 16.5% after the Federal Motor Transport Authority in Germany cleared Tesla's Model S of any manufacturing defects following a series of three fires in a matter of six weeks. The National Highway Traffic Safety Administration in the U.S. has yet to release its findings, but chances are good that Tesla shares could rally further if the NHTSA finds no defects with the Model S as well. As for me, I remain short shares of Tesla Motors, as I find the valuation on a per-car basis, the series of missed building deadlines, the high-cost and uncertainty of a production ramp-up, and a lack of EV long-range infrastructure, to be a deterrent to its frothy share price.

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The article Why OncoMed Pharmaceuticals, Unilife, and Tesla Motors Are Today's 3 Best Stocks originally appeared on Fool.com.

Fool contributor Sean Williams is short shares of Tesla Motors, but has no material interest in any other companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.The Motley Fool recommends Celgene, Ford, General Motors, and Tesla Motors. The Motley Fool owns shares of, and recommends Ford and Tesla Motors. It also recommends Celgene and General Motors. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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